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Tablets & Capsules October 2017 45 Unfortunately, because the treatment only retards further vision degenera- tion while the API is present, treat- ments must be continued indefinitely to prevent further deterioration. It's not surprising that patient compliance is a challenge, as is the impact on the ophthalmologists who administer the treatments. Available solutions. At TruTag Technologies, we have developed state-of-the-art, cGMP-compliant poSi manufacturing lines to fabricate optical microtags for product iden- tity and precision micro-particles for sustained drug delivery. For product identity, we combine our silica microtag technology with our pro- prietary optical readers to create a fully integrated solution for pharma- ceutical and nutraceutical manufac- turers to use in combating drug prod- uct counterfeiting and diversion. And we are now partnering with a drug delivery biotech firm to use our poSi micro-particles to address the grow- ing AMD treatment market. lar organelles. These materials are typ- ically introduced into the bloodstream by intravenous injection. While func- tionalizing poSi at a nanoparticle level is still an immature technology, it holds tremendous promise in applica- tions such as antitumor therapies. Sustained delivery. Mesoporous silica particles have also been used in sustained-release drug delivery appli- cations. Benefits of sustained drug delivery include significantly less fre- quent treatments, which can reduce costs and risks from treatment compli- cations, especially when drug prod- ucts are administered by injection. In sustained-release applications, the poSi particles are loaded with one or more APIs, which adsorb on the outer surface and the internal pore surfaces. The API release profile is affected by the balance between surface adsorp- tion and how the API molecule inter- acts with the dissolution medium. The stronger the adsorption to the surface, the slower the release. Some studies have shown that the release, or elu- tion, profile follows a well-known model defined by the Higuchi equa- tion. Others have shown a two-step elution profile, whereby there is an initial release burst followed by a slower release profile. The initial elu- tion burst is thought to come from API molecules that are adsorbed on the outer particle surfaces and the near-surface regions of the pores, where the dissolution medium can reach the API relatively unobstructed. Then, as the near-surface API material dissolves, the dissolution medium must diffuse further into the nanome- ter-scale pores to reach more API molecules, thus hindering dissolution and reducing the rate of elution. One promising application is treat- ing age-related macular degeneration (AMD), which affects an estimated 11 million people in the USA and is the leading cause of irreversible blindness and visual impairment in the world. Current treatment regimens require intraocular injections about every 4 to 8 weeks. With each injection comes a level of pain and discomfort, as well as injection-related risks such as endoph- thalmitis and retinal detachment. Conclusion Silica as an excipient has been around for decades in food and phar- maceutical products that we consume every day. With new, advanced tech- nologies being developed in silica material technologies, many new and exciting tools are being created for addressing major challenges such as counterfeiting, product diversion, therapy effectiveness, and patient compliance. T&C Reference 1. Guidance for Industry: Incorporation of Physical-Chemical Identifiers into Solid Oral Dosage Form Drug Products for Anticounter- feiting. October 2011. Craig Leidholm is senior vice president, mate- rials manufacturing, at TruTag Technolo- gies, 2045 Lauwiliwili Street, Unit 301, Kapolei, HI 96707. Tel. 808 878 8247. Website: www.trutags.com.